H-M Supporter - Gold Member

Several years ago I made some frame flugs for my motorcycle. I had to reduce the thread size of a few socket head screws to get the thread size that would fit and maintain the head size that I thought looked porportional to the plug. I used box store quality black oxide screws.

Now these screws are rusting.

Have any ideas of a solution, keeping in mind that I will be machining off part of any plating and the hex still needs to fit a wrench (powder coat would be too thick),

The plugs themselves are powder coated (satin) clear so I think they will clean up OK. And, I don't remember what sizes I started with! I will edit this post as soon as I take them out to see if I can clean them up.

H-M Supporter - Gold Member

How about brass? I believe that Birchwood Casey makes a brass blackening solution.

Another possibility would be to remove the original black oxide and reoxidize using cold bluing solution.. I have restore antique hardware by flame oxidizing and coating with automotive clear coat., Twelve years down the road and no sign of rusting. Or just buy new bolts and coat with acrylic.

My experience with powder coating has all been negative. As long as the coating is intact, everything is fine but if the coating integrity is breached, water gets behind the coating and it rusts from the back side. Then whole slabs of powder coat come off.

H-M Supporter - Commercial Member

How about brass? I believe that Birchwood Casey makes a brass blackening solution.

Another possibility would be to remove the original black oxide and reoxidize using cold bluing solution.. I have restore antique hardware by flame oxidizing and coating with automotive clear coat., Twelve years down the road and no sign of rusting. Or just buy new bolts and coat with acrylic.

My experience with powder coating has all been negative. As long as the coating is intact, everything is fine but if the coating integrity is breached, water gets behind the coating and it rusts from the back side. Then whole slabs of powder coat come off.

You mean like paint? I think each type of coating has its good and bad attributes. Powder coating will be very durable and if done correctly is a very good coating. If you have big hunks of powder coating coming off then the material was not prepared properly. Powder coating requires very meticulous preparation just like paint and in some cases more so.

H-M Supporter - Gold Member

Yeah, brass, stainless or even titanium would eliminate the rust but a bright color just doesn't look good. I think they need to be black just for aesthetics.

I powder coat a lot of stuff and am not worried about the process or durability (the plugs themselves are powder coated black with a clear coat of satin powder coated). However powder coating is too thick to allow me to get a hex wrench into the screw. Even other types of paint (acrylic, lacquer, enamel, etc) pose a problem when inserting the hex wrench. I suppose I could grind or make a "special" hex wrench but . . .

I thought about nylon screws but I can't find any metric sizes in black.

I think for now I will try killing the rust with evapo-rust and/or vinegar, paint the outside with black acrylic (or some paint) and try touching up the hex with a tiny brush after they are installed. I've tried touching them up before but that was after the rust had started. Maybe if they are properly prepped first? That would save me the trouble of reducing the threads on those screws - which is harder than you would think!)

H-M Supporter - Gold Member

Yeah, brass, stainless or even titanium would eliminate the rust but a bright color just doesn't look good. I think they need to be black just for aesthetics.

I powder coat a lot of stuff and am not worried about the process or durability (the plugs themselves are powder coated black with a clear coat of satin powder coated). However powder coating is too thick to allow me to get a hex wrench into the screw. Even other types of paint (acrylic, lacquer, enamel, etc) pose a problem when inserting the hex wrench. I suppose I could grind or make a "special" hex wrench but . . .

I thought about nylon screws but I can't find any metric sizes in black.

I think for now I will try killing the rust with evapo-rust and/or vinegar, paint the outside with black acrylic (or some paint) and try touching up the hex with a tiny brush after they are installed. I've tried touching them up before but that was after the rust had started. Maybe if they are properly prepped first? That would save me the trouble of reducing the threads on those screws - which is harder than you would think!)

H-M Supporter - Gold Member

Yeah, brass, stainless or even titanium would eliminate the rust but a bright color just doesn't look good. I think they need to be black just for aesthetics.

I powder coat a lot of stuff and am not worried about the process or durability (the plugs themselves are powder coated black with a clear coat of satin powder coated). However powder coating is too thick to allow me to get a hex wrench into the screw. Even other types of paint (acrylic, lacquer, enamel, etc) pose a problem when inserting the hex wrench. I suppose I could grind or make a "special" hex wrench but . . .

I thought about nylon screws but I can't find any metric sizes in black.

I think for now I will try killing the rust with evapo-rust and/or vinegar, paint the outside with black acrylic (or some paint) and try touching up the hex with a tiny brush after they are installed. I've tried touching them up before but that was after the rust had started. Maybe if they are properly prepped first? That would save me the trouble of reducing the threads on those screws - which is harder than you would think!)

At the machine shop where I am employed we make bass guitar components that terminate the strings from stainless steel, some are black oxided after machining for appearance only, this is also a durable finish process, not nearly as durable as black chrome however but far less expensive.

At the machine shop where I am employed we make bass guitar components that terminate the strings from stainless steel, some are black oxided after machining for appearance only, this is also a durable finish process, not nearly as durable as black chrome however but far less expensive.

Great info & idea. I did a search and found several places that stock black chrome plated metric socket head screws. You are right though, they are expensive - a bag or 10 for $20 and I need a couple of bags to get different sizes. But still, they seem like the answer to my problem. And I've learned that you can't look at the prices of Ducati parts without risk of sudden cardiac arrest.